So...I am very much infatuated by the science behind triathlons and have recently been looking at power meters. I will be doing IMLP and am planning a few other distances in preparation for the IM. (This will be my first full.) I am riding a Specialized Shiv (SRAM components).

I have done a bit of research and pondering the purchase of a power meter, but wanted to hear some thoughts on this topic from you!

Is a power meter worth the investment?

If answer to the above questions is "yes", which power meter would you recommend?

IMLP is a relatively hilly course. While a powermeter would be helpful, a heart rate monitor and wide gearing (50/34 chainrings, 12-32 cassette) would be significantly more cost effective in keeping a consistent effort. If cadence is too slow/ force too high, lactic acid builds up very quickly. If cadence it too high, then technique suffers. Somewhere between is a range of about 15 RPM that will be optimal. The heart rate meter will ensure the right amount of effort is being applied. Power meters are for the pros.

IMLP? yes! If you like training with data- then you will LOVE having a power meter.

the most cost effective one right now is from Stages ~$700 and it comes on a Rival crank arm. So, that, presumably, would fit right onto your Shiv. I'd also recommend the Stages if you already have a set of aero race wheels that you intend to use.

If not, and you train on a road bike as well as your TT bike, and your roadie has shimano cranks or another brand, then you might want to look at a powertap. They are the hub of your rear wheel. you can buy just the hub and build up a wheel around it, or buy it in a wheel. I just saw some on sale for as low as $800. And you can find a good used powertap in a wheel for $600-$700. The wheel is then easy to swap between your roadie and TT bike. And you put a Wheelbuilder cover on it for race day and you're set.

it will change the way you ride and train. it will keep you 'honest' on race day, preventing you from overdoing it and ultimately resulting in a faster day.

but just having the power meter and a display showing you your watts is only the beginning. Buy and read "Racing and Training with a Power Meter". Download Golden Cheetah (free, for macs), or use Training Peaks to analyze your training and have a great time.

I was in the bike shop last night and the guy there told me the Garmin Vectors are going to finally start shipping next month. While i am still a little skeptical, that is great news. I have been looking at power meters, and think a pedal based system would be awesome.

If not, and you train on a road bike as well as your TT bike, and your roadie has shimano cranks or another brand, then you might want to look at a powertap. They are the hub of your rear wheel. you can buy just the hub and build up a wheel around it, or buy it in a wheel. I just saw some on sale for as low as $800. And you can find a good used powertap in a wheel for $600-$700. The wheel is then easy to swap between your roadie and TT bike. And you put a Wheelbuilder cover on it for race day and you're set.

it will change the way you ride and train. it will keep you 'honest' on race day, preventing you from overdoing it and ultimately resulting in a faster day.

but just having the power meter and a display showing you your watts is only the beginning. Buy and read "Racing and Training with a Power Meter". Download Golden Cheetah (free, for macs), or use Training Peaks to analyze your training and have a great time.

That's my plan, and my Black Friday / Christmas shopping list. Powertap wheel for training, plus a disc cover for racing. The Qarq / SRM / crank-based power meters are cool, but about three times the cost, and without the ease of swappping. The downside of the powertap is not running fancy race wheels, but I figure I'll get a fancy front wheel and run a disc cover on the back.

IMLP is a relatively hilly course. While a powermeter would be helpful, a heart rate monitor and wide gearing (50/34 chainrings, 12-32 cassette) would be significantly more cost effective in keeping a consistent effort. If cadence is too slow/ force too high, lactic acid builds up very quickly. If cadence it too high, then technique suffers. Somewhere between is a range of about 15 RPM that will be optimal. The heart rate meter will ensure the right amount of effort is being applied. Power meters are for the pros.

I think a power meter can be helpful, but for a first IM I would agree with you and say a HR monitor is really all you need. I used it during my training and i knew exactly where I was in terms of RPE at each HR. Also, it allowed me to not overdo the hills and it allowed me to really push on the flats and the downhills without going over my threshold.

Whatever you choose, I think what's most important is that you really dial in on the data during your training and how your body feels/responds with that data. For IMLP all my training was focused around the my magic number of 167. Under 167 was my Z2 and I felt like I could run/bike forever and not burn out. Above 167 I knew I would started accumulating that lactic acid and my pace would suffer. During my short hard workouts I would try to push above 167 to 180 and for my easy long workouts I would try to stay under 167 as low as 155. On race day I was able to stay in my HR zone on the bike and really push out a strong marathon because of it.

I've become a MUCH better cyclist since moving from HR/RPE to power. Dramatic gains, if used properly. For me, especially for long course, it's a more effective pacing tool than any other metric. The pt g3 just dropped $500 in price so I bet you could find a pro (the prior model) pretty cheap soon. Eta I train on a pt wheel and cover it for races. Wicked cheap and fast

Originally posted by allison_h Thank you both for your responses! This is a huge help! I am definitely trying to understand all this and absorb every bit of knowledge that I can. @morey000 -Thank you for the book recommendation, I am checking that out now. Allison

you're welcome.

there are posts above that tout the glories of RPE/HR. The reality is that RPE is really inaccurate, and HR, while more accurate- is slow to respond to your efforts and drifts over time with hydration and body temp. Of course- with experience you can learn to be more sensitive to how your body is responding, and there's no doubt that you can become a tremendous cyclist without ever looking at your power data, but there's also no doubt that a power meter will provide you more accurate data on your output. I can't tell you how many times I've said to myself- OK- I want to hold 180 watts. I look at the meter and see that I'm doing 180w. then I look away from the meter for 2 minutes, try to hold the same effort, and then see where I am. Lucky if I'm within +/- 20%. Perhaps that says I need to concentrate more on awareness of my body- probably true, but it's nice to have the feedback of a meter that's accurate to within a percent or two.

the reality is- the difference between holding 70% and 85% of your FTP for 6 hours is hard to distinguish by RPE, but will make a huge difference in your run. You can even target an optimal TSS for your IM ride, that leaves you a balance left for the run.

I can't tell you how many times I've started in on the bottom of a long hill, with the thought that I was going to take it easy at the start, and looked down to find that I'm averaging 20% above my FTP. I can't feel it yet, but in 1 minute, my legs are going to fatigue and I won't be able to hold that level. HR hasn't told me yet. RPE hasn't told me yet. This is one of the ways that a power meter really helps for a IM. It can prevent you from 'burning your matches' during a long race. Without the meter, you'll approach a hill during your Lake Placid ride and over-do it just a little. You'll back off as soon as you feel the fatigue setting in- but now it's too late. you've burned a match. You just saved 10 seconds on this climb... that will cost you 20 seconds on the run... and you'll never know it.

From a training perspective- using the exercise science tools (training peaks/golden cheetah) now readily available to track your training loads, is truly amazing.

It's not for everyone. I totally get it that some would rather get out there, work hard, have fun and improve and not be burdened with a bunch of numbers. In my own case- the numbers probably hold me back as much as they help me (oh, I've got too much ATL built up this week, I better back off...). I'm not much of a cyclist- more of a swimmer and runner. But - if you like numbers and want a tool to help you train and race- then there's nothing better than a power meter. Certainly not RPE and HR.